绣花鞋上的一朵盛花——探寻壮族绣花鞋之美

壮族是我国人口数量最多的少数民族,悠久的历史创造出绚烂的民族文化与艺术。壮族的绣花鞋色彩艳丽,图案丰富,与传统壮族服饰相比形成反差之美,其不仅代表民族民间美术,也蕴含着民族艺术审美。依次从绣花鞋的制作、款式、图案介绍壮族绣花鞋,黑衣下的一朵艳丽盛花。     

Detection of colorectal liver metastases: prospective comparison of unenhanced and ferumoxides-enhanced magnetic resonance imaging at 1.5 T, dual-phase spiral CT, and spiral CT during arterial portography

The purpose of this study was to compare the efficacy of unenhanced and ferumoxides-enhanced magnetic resonance imaging with that of dual-phase spiral CT and spiral CT during arterial portography (CTAP) for the detection of colorectal liver metastases. Fourteen patients with liver metastases candidates for partial hepatectomy were examined with dual-phase spiral CT, unenhanced and ferumoxides-enhanced MR imaging at 1.5 T, and spiral CTAP. Imaging tests were read blinded, prospectively, quantitating number of lesions excepting CTAP which used US to exclude cysts. Subsequent intraoperative US and pathologic findings were correlated with preoperative imaging results. At surgery, 36 lesions 0.5–13 cm in diameter (mean ±standard deviation, 2.9±2.1 cm) were identified. Dual-phase spiral CT depicted 21/36 (58%); precontrast MR imaging, 19/36 (53%); ferumoxides-enhanced MR imaging, 30/36 (83%); and spiral CTAP, 34/36 (94%) lesions. Ferumoxides-enhanced MR imaging was significantly more sensitive than spiral CT and unenhanced MR imaging (P<0.01). The difference in sensitivity between ferumoxides-enhanced MR imaging and spiral CTAP was not statistically significant (P>0.1). Spiral CTAP, however, depicted nine false-positive lesions (2 hemangiomas, 7 perfusion defects). The positive predictive value was 79% for spiral CTAP and 100% for combined pre- and postcontrast MR imaging. We conclude that ferumoxides-enhanced MR imaging is superior to unenhanced MR imaging and biphasic spiral CT for depiction of colorectal liver metastases. Further investigation is needed to clarify whether MR imaging with use of ferumoxides might replace spiral CTAP for preoperative evaluation of liver resection candidates. Recipient of a Cum Laude award for a scientific exhibit at the 1997 ESMRMB annual meeting.     

From a scholar city to a solar city

Located on “Bartolomé Masó” municipality on the north part of “Sierra Maestra” in “Granma” province, the Scholar City “Camilo Cienfuegos”, represents a paradigm of the real ideals of the Cuban Revolution related to education. The paper presents the results of a work developed by a team of professors and students of the Faculty of Architecture and Mechanic Engineering in the Polytechnic University of Havana (ISPJAE) in 1997, which includes a diagnosis of its current situation as a consequence of its historical development, and an strategy for its transformation into a sustainable city.The proposed strategy deals with economic and social sustainability, preservation of natural resources, energy conservation, and appropriate technology, considered in 3 main concepts: Habitat city, Cultural city, and Sustainable city, which are finally integrated into a Solar City as a symbolic term. As part of the proposal, a Master Plan, urban and architectural design criteria and steps for the future development are presented.     

Vertical glaciology: The second discovery of the third dimension in climate research

The history of climate research in the 20th century has been characterised by a crucial shift from a geography-oriented, two-dimensional approach towards a physics-based, three-dimensional concept of climate. In the 1930s, the introduction of new technology, such as radiosondes, enabled climatologists to investigate the high atmosphere, which had previously been out of reach. This “conquest of the third dimension” challenged the surface-oriented, geographical notion of climate patterns and opened up climatology to a three-dimensional approach, which deeply changed the character of climate research. Two decades later, by drilling deep into polar glaciers and using the downward vertical dimension as an archive of the earth's history, ice core scientists began to reconstruct past climates layer by layer. The data retrieved in deep glacial layers contributed crucially to a temporal expansion of climate history far beyond human timescales. However, the inaccessibility of glaciers and the practical challenges of bringing fragile fragments of ice into transnational networks of scientific exchange meant that this vertical extension of climate knowledge production proceeded through a range of new scientific practices, and was shaped by new forms of international collaboration. Furthermore, this vertical approach to glaciers also asked for a new understanding of glacier volume. Drawing on archival and printed sources, I argue that ice core research represented a second discovery of the third dimension, this time downwards into the depth of the earth's surface, but again with decisive consequences for the research practice, for collaboration politics, and for understandings of climate, spatially as well as temporally.     

Cloning of the Penicillium minioluteum gene encoding dextranase and its expression in Pichia pastoris

The DEX gene encoding an extracellular dextranase was isolated from the genomic DNA library of Penicillium minioluteum by hybridization using the dextranase cDNA as a probe. Comparison of the gene and cDNA sequences revealed that the DEX gene does not contain introns. Amino acid sequences comparison of P. minioluteum dextranase with other reported dextranases reveals a significant homology (29% identity) with a dextranase from Arthrobacter sp. CB-8. The DEX gene fragment encoding a mature protein of 574 amino acids was expressed in the methylotrophic yeast Pichia pastoris by using the SUC2 gene signal sequence from Saccharomyces cerevisiae under control of the alcohol oxidase-1 (AOX1) promoter. Over 3·2g/l of enzymatically active dextranase was secreted into the medium after induction by methanol. The yeast product was indistinguishable from the native enzyme in specific activity and the N-terminus of both proteins were identical.     

In Silico and In Vitro Studies of Benzothiazole-Isothioureas Derivatives as a Multitarget Compound for Alzheimer’s Disease

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder. Inhibiting acetylcholinesterase (AChE), amyloid beta (Aβ_1-42) aggregation and avoiding the oxidative stress could prevent the progression of AD. Benzothiazole groups have shown neuroprotective activity whereas isothioureas groups act as AChE inhibitors and antioxidants. Therefore, 22 benzothiazole-isothiourea derivatives (3a–v) were evaluated by docking simulations as inhibitors of AChE and Aβ_1-42 aggregation. In silico studies showed that 3f, 3r and 3t had a delta G (ΔG) value better than curcumin and galantamine on Aβ_1-42 and AChE, respectively. The physicochemical and pharmacokinetics predictions showed that only 3t does not violate Lipinski’s rule of five, though it has moderated cytotoxicity activity. Then, 3f, 3r and 3t were synthetized and chemically characterized for their in vitro evaluation including their antioxidant activity and their cytotoxicity in PC12 cells. 3r was able to inhibit AChE, avoid Aβ_1-42 aggregation and exhibit antioxidant activity; nevertheless, it showed cytotoxic against PC12 cells. Compound 3t showed the best anti-Aβ_1-42 aggregation and inhibitory AChE activity and, despite that predictor, showed that it could be cytotoxic; in vitro with PC12 cell was negative. Therefore, 3t could be employed as a scaffold to develop new molecules with multitarget activity for AD and, due to physicochemical and pharmacokinetics predictions, it could be administered in vivo using liposomes due to is not able to cross the BBB.     

Detection and Mitigation of Impulsive Interference on OFDM Signals Based on Spectrum Sensing,Blanking and Symbol Retransmission

The increasing number of wireless devices and systems operating on the same area leads to significant interference problems that need to be solved. This paper deals with detection and mitigation of the interference generated by an impulsive noise source on an orthogonal frequency division multiplexing system. The idea proposed here is to overcome the interference problem by exploiting the transmission of two replicas of the symbol affected by interference, that are suitably combined at the receiver after a blanking operation of the corrupted samples. An energy detection based sensing scheme is used to reveal the presence of interference. The proposed method allows to efficiently remove the interference without affecting the useful information and exploiting profitably the diversity gain against noise through the soft combining approach. Performance in terms of bit error rate and throughput is compared with the case without mitigation and with the classical blanking method showing a significant improvement. The reduction of the transmission rate, due to the retransmissions, is well compensated by the improvement of the data reliability that leads to an increase of useful data correctly received.     

AI Based Network and Radio Resource Management in 5G HetNets

The demand for pervasive wireless access and high data rate services are expected to grow significantly in the near future. In this context, the deployment of Heterogeneous Networks (HetNets) will enable important capabilities, such as high data rates and traffic offloading, providing dedicated capacity to homes, enterprises, and urban hotspots. Despite HetNet technology will be beneficial for future wireless systems in many ways, the massive cells diffusion has as a consequence an exponential increase of the backhaul traffic that can create congestion and collapse the backhaul network. Virtualization of networks and radio access allows the implementation of complex and efficient decisional processes for radio and network resource optimization, but the interaction between lower and upper layers during resource allocation decisions is still mostly unexplored. In this paper we propose an artificial intelligence based approach, with two interdependent decisional cores exchanging information, one aware of physical layer aspects and the other controlling pure network resources. The two iterative procedures aim at jointly optimizing the distribution of the traffic in the backhaul network and the users cell association, with the goals of minimizing the unsatisfied users data rate requests and minimizing the energy consumption reducing the number of activated cells, respectively.     

Autofluorescence and diffuse reflectance spectroscopy of oral epithelial tissue using a depth-sensitive fiber-optic probe

Optical spectroscopy can provide useful diagnostic information about the morphological and biochemical changes related to the progression of precancer in epithelial tissue. As precancerous lesions develop, the optical properties of both the superficial epithelium and underlying stroma are altered; measuring spectral data as a function of depth has the potential to improve diagnostic performance. We describe a clinical spectroscopy system with a depth-sensitive, ball lens coupled fiber-optic probe for noninvasive in vivo measurement of oral autofluorescence and diffuse reflectance spectra. We report results of spectroscopic measurements from oral sites in normal volunteers and in patients with neoplastic lesions of the oral mucosa; results indicate that the addition of depth selectivity can enhance the detection of optical changes associated with precancer.     

Native carotenoids composition of some tropical fruits

Many tropical fruits can be considered a reservoir of bioactive substances with a special interest due to their possible health-promoting properties. The interest in carotenoids from a nutritional standpoint has recently greatly increased, because of their important health benefits. Here we report the native carotenoids composition in six tropical fruits from Panama, which is considered a region of great biodiversity. The native carotenoid composition was directly investigated by an HPLC-DAD-APCI-MS methodology, for the first time. In Corozo 32 different carotenoids were detected, including a high content of β-carotene and lycopene. Sastra showed the highest content of zeaxanthin among the fruit investigated. In Sapote 22 different carotenoids were detected, including β-carotene and 10 different zeaxanthin-di-esters. Frutita showed a very high content of the apo-carotenoid β-citraurin, and of a number of its esters. In Maracuyà chino 14 carotenoids were detected, including a high amounts of mono-esterified lauric acid with β-cryptoxanthin and with cryptocapsin. Mamey rojo was characterised by ketocarotenoids with κ rings, both hydroxylated and not hydroxylated.